Various imidazole urea compounds are disclosed in U.S. Pat. No. 3,983,135 as being central nervous system depressants. One of these is 1-meta-chlorophenyl-3-(1-methyl-4-oxo-2-imidazolidinylidene)urea, also known by the name N-3-chlorophenyl-N'-(4,5-dihydro-1-methyl-4-oxo-1H-imidazol-2-yl)urea or Fenobam (CAS Registry No. 63540-28-3). Also known are 1-(tetrahydro-1-alkyl-4-oxo-1H-imidazol-2-ylidene)-3-thienyl-ureas disclosed in U.S. Pat. No. 4,230,713 as anxiolytic agents.
The alkoxycreatinines 5-ethoxy-, 5methoxy-, 5-n-propoxy and 5-n-butoxycreatinine were described without any mention of biological activity, by G. B. Chheda et al. at the 32nd Annual Conference on Mass Spectrometry and Allied Topics, May 27-June 1, 1984, San Antonio, Tex., at a poster session and by A. Arakali et al. at the 188th National Meeting of the American Chemical Society, Philadelphia, Pa., Aug. 26-31, 1984 in the Division of Medicinal Chemistry presentation No. 65.